diketahui fungsi f(x) = ax + b. jika f(-1) = -7 dan f(4) = 18, tentukan : a. nilai a dan b. b. rumus fungsi f(x). c. nilai f(-3) dan f(7). d. nilai k sehingga f

a. nilai a dan b

f(x) = ax + b
f(-1) = -a + b = -7
f(4) = 4a + b = 18

eliminasi b

5a =25
a = 25/5
a = 5

substitusi nilai a ke salah satu persamaan

4a + b = 18
4(5) + b = 18
20 + b = 18
b = 18 - 20 = -2

b. rumus fungsi f(x)

f(x) = ax + b
f(x) = 5x - 2

c. nilai f(-3) dan f(7)

f(x) = 5x - 2
f(-3) = 5(-3) - 2 = -15 - 2 = -17

f(x) = 5x - 2
f(7) = 5(7) - 2 = 35 - 2 = 33

d. nilai k sehingga f(k) = 8

f(x) = 5x - 2
f(k) = 5k - 2 = 8

5k - 2 = 8
5k = 8 + 2
5k = 10
k = 10/5
k = 2

semoga membantu###